Adjustable cam stop for rotary vane motors



Jan. 9, 1968 H. J. SHAFER 3,362,300

ADJUSTABLE CAM STOP FOR ROTARY VANE MOTORS Filed July 1, 1965 2Sheets-Sheet 1 INVENTOR. HOMER-LSHAFER ATTORNEYS H. JFSHAFER 3,362,300 OADJUSTABLE CAM STOP FOR ROTARY VANE MOTORS Jan. 9, 1968 2 Sheets-Sheet 2Filed July 1, 1965 2 3 H w m 2 2 0 2 2 IIEI x W I m r 2 INVENTOR. HOMERJ. SHAFER 7 ATTORNEYS United States Patent 3,362,300 ADJUSTABLE CAM STOPFOR ROTARY VANE MGTORS Homer J. Shafer, 2300 Park Ave. W., Mansfield,Ohio 44906 Filed July 1, 1965, Ser. No. 468,710 2 Claims. (Cl. 92-13)The present invention relates to rotary or oscillating vane hydraulicvalve operator motors, and more particularly to adjustable stops forabutting the motor vanes.

In rotary vane hydraulic motors used as operators for large pipelinevalves, the motor must be precisely aligned with the valve so that therotary travel of the vanes terminates exactly at the fully closed andfully open positions of the valve, and adjustment of the stops for thevanes to accomplish this result should be made externally of the motorto save time and enable adjustments while the motor is filled withhydraulic fluid under high pressure.

One form of adjustable stop is shown and described in US. Patent No.3,171,332, issued Mar. 2, 1965, comprising a stop which slidably abuts astationary shoe defining the internal pressure chamber of the motor, andwhich has a beveled edge for stopping rotation of the vane, with anadjustment stud screwed into the stop for sliding it radially of theshoe.

A major disadvantage of this prior stop is that when the vane strikesthe stop the high pressure on the vane is transmitted to the stationaryshoe and tends to loosen and displace it during repeated use. Also, theprior stop is relatively expensive to manufacture, and requiresmachining of the abutment surface on the shoe.

It is an object of the present invention to provide improved adjustablestop means for a hydraulic rotary vane motor to precisely limit therotary movement of the vanes.

Another object is to provide improved stop construction which isadjustable externally of the motor while it is filled with high pressurefluid.

A further object is to provide improved stop means which transmits thepressure on the vane to the wall of the motor.

A still further object is to provide improved stop means which isinexpensive to manufacture and does not require machining of theinternal shoe.

These and other objects are accomplished by the improvements of thepresent invention which are described in the specification and shown inthe drawings herein, and which are defined in the claims, along withvarious modifications and variations in construction.

Referring to the drawings:

FIG. 1 is a plan section view, partly in elevation, of a rotary vanemotor embodying the invention.

FIG. 2 is a vertical sectional view taken on line 22 of FIG. 1.

FIG. 3 is a fragmentary sectional view on line 3-3 of FIG. 1.

FIG. 4 is a perspective view of the adjustable cam stop detached fromthe assembly.

The rotary vane motor preferably includes a cylindrical casing havingtop and bottom cover plates 11 and 12, respectively, forming a closedcylindrical chamber, the plates being secured to the casing 10 bycircumferential rows of screw studs 14. The joints between the casingand the plates may be sealed by O-ring gaskets 15.

The rotor 16 comprises a hub 17 having its ends journaled in the endplates 11 and 12 by sleeve bearings 18 and 19, respectively, and thebearings each have O-rings 20 at the bearing surface to prevent leakageof hydraulic fluid from the motor and to keep out foreign matter.

Each sleeve bearing preferably has a pair of fluid and dust sealingO-rings 21 surrounding the bearing and located in annular grooves in thecover plates 11 and 12. Between each pair of rings 21 is .an annulargroove 22 and 23, respectively.

The rotor hub 17 has an axial bore 24 extending there through with oneor more keyways 25 for splined mounting on the stem of a rotary valve(not shown) which may be a plug valve or a ball valve. The manner ofsupporting the rotary vane motor on the rotary valve per se forms nopart of the invention and is not shown.

The rotary vane motor has a pair of diametrically opposite stationaryshoes 26A and 26B disposed within the motor chamber to bisect it intotwo chambers within which the vanes 27 of the rotor oscillate. Each shoepreferably comprises a rectiliner block with at least one rectilinearO-ring 28 carried in a groove extending around the vertical perimeter ofthe block. The shoes 26 have a close tolerance fit with the rotor andthe inside wall of the casing 10, and the O-rings 28 provide effectiveseals preventing leakage of hydraulic fluid between the two chambers ofthe motor. As shown, the shoes may be secured to the top and bottomplates 11 and 12 by screw studs 30.

The rotor vanes 27A and 27B may be blocks welded to the rotor hub atdiametrically opposite locations, or may be integrally formed with therotor hub or attached thereto by other suitable means. As shown in FIG.2, each vane preferably has at least one rectilinear O-ring 32 disposedsubstantially around its vertical perimeter in continuous fluid-tightengagement with the inner wall of the casing 10, and with the end plates11 and 12 to prevent leakage of fluid past the vane as it oscillates inthe motor chamber.

Suitable external pressure and exhaust connections 29 and 29A areprovided for supplying hydraulic fluid to the motor and exhausting ittherefrom. Also, crossover porting is preferably provided for balancedtorque operation by directing pressure fluid to opposite sides of bothvanes simultaneously. Thus, the annular grooves 22 and 23 are connectedby ports 31 to the chambers on opposite sides of the vanes. The detailsof the supply and exhaust and crossover porting form no part of thepresent invention, and may be further explained by reference to PatentNo. 2,811,142, dated Oct. 29, 1957.

As shown in FIG. 1, there are four adjustable cam stops indicatedgenerally at 33, one at each end of each of the two motor chambersformed by the diametrically opposite shoes 26A and 26B. It will beunderstood that only two cam stops may be used, one on either side ofone of the shoes 26A, for example, in which case vane 27A. abuts one ofthe stops at one end of the rotor travel, and vane 27B abuts the otherof the stops at the other end of the rotor travel. The use of four stopsis preferred to provide balanced torque on the rotor when it is stoppedat either end of the rotor travel corresponding to the fully open andfully closed positions of the valve.

The improved cam stops 33 each preferably comprise a shank 34 extendingthrough a close fitting bore 35 in the cylinder wall, and having anintegral cam 36 on its inner end and a threaded portion 37 at its outerend, with a squared wrench-engaging portion 38. The shank has an O-ringgroove 39 for receiving an O-ring 40 to make a seal between the shank'34 and the bore 35. Adjacent to the cam 36 is an annular shoulder 41which is adapted to seat against an internal spot face 42 which is aplanar annular'surface surrounding the bore on the inner surface of thecasing 10.

A tapered locking bushing 43 is seated in a tapered socket at the outerend of bore 35 for abutting a lock nut 44 screwed on the threadedportion 37 of the shank aseasns to lock the shank against turning in thebore after it has been adjusted.

As best shown in FIG. 3, the cam 36 has a substantially spiralperipheryterminating at an outer point, so that rotation of the campresents a cam edge of varying radius to afford an adjustable stop forthe vane at the end of its travel in one direction. By rotating theposition of the cams, they can be adjusted accurately to stop the rotorexactly at the fully open and fully closed positions of the valve. Thecams are designed to provide a total angular adjustment of the rotor ofabout two and one-half degrees.

The adjustment is easily made externally of the fluid motor after it isassembled and filled With fluid under pressure. All that is necessary isto loosen the lock nut 4-4 and then rotate the shank 34 by applying aWrench t the squared end 33. \Vhen the adjusted position has beenlocated, the lock nut 44 is tightened to maintain the cam stop inposition.

Each time the vane abuts the cam at the end of its travel, the impact istransmitted through the shoulder 41 abutting spot face 42 to thecylinder Wall 11 and not to the adjacent shoe 26A or 26B as is the caseWith the stop in Patent No. 3,171,332. Thus the shoes are not subjectedto any impacts tending to cause them to work loose. Moreover, nomachining of the shoes is required to provide an abutment face thereon.

It is apparent that the objects of the invention are accomplished by theimproved adjustable cam stop which is inexpensive to manufacture, andeasy to adjust externally of the hydraulic motor.

What is claimed is:

1. In a rotary vane fluid motor having a closed cylindrical housing, arotor hub having a vane oscillatable in said housing, and means defininga pressure chamber Within which the vane oscillates, the improvementcomprising an adjustable cam stop for abutting the vane to limit itsmotion, said cam stop having a shank extending through said housing fortransmitting the pressure from the vane to said housing, said cam stophaving an internal shoulder with a planar surface, a planar spot face onthe inner surface of said housing abutting the planar surface of saidshoulder, an integral cam on the inner end of said'shank having a spiralperipheral surface for surface abutment With the vane in variouspositions of adjustment, and means on the outer end of said shank forlocking said stop with said cam in a position of rotary adjustment.

2. A device as defined in claim 1 in which said locking means comprisesa tapered lock bushing in said housing engaging said shank, and a nutscrewed on the outer end of said shank in abutment with said bushing forclamping said shoulder in abutment with said spot face and for lockingsaid cam stop With said cam in a position of rotary adjustment.

References Cited UNiTED STATES PATENTS 1,870,296 8/1932 Schnell 74-5681,880,375 10/1932 Davis. 3,171,332 3/1965 Randle 92-13 MARTIN P.SCHWADRON, Primary Examiner.

1. IN A ROTARY VANE FLUID MOTOR HAVING A CLOSED CYLINDRICAL HOUSING, AROTOR HUB HAVING A VANE OSCILLATABLE IN SAID HOUSING, AND MEANS DEFININGA PRESSURE CHAMBER WITHIN WHICH THE VANE OSCILLATES, THE IMPROVEMENTCOMPRISING AN ADJUSTABLE CAM STOP FOR ABUTTING THE VANE TO LIMIT ITSMOTION, SAID CAM STOP HAVING A SHANK EXTENDING THROUGH SAID HOUSING FORTRANSMITTING THE PRESSURE FROM THE VANE TO SAID HOUSING, SAID CAM STOPHAVING AN INTERNAL SHOULDER WITH A PLANAR SURFACE, A PLANAR SPOT FACE ONTHE INNER SURFACE OF SAID HOUSING ABUTTING THE PLANAR SURFACE OF SAIDSHOULDER, AN INTERGRAL CAM ON THE INNER END OF SAID SHANK HAVING ASPIRAL PERIPHERAL SURFACE FOR SURFACE ABUTMENT WITH THE VANE IN VARIOUSPOSITIONS OF ADJUSTMENT, AND MEANS ON THE OUTER END OF SAID SHANK FORLOCKING SAID STOP WITH SAID CAM IN A POSITION OF ROTARY ADJUSTMENT.